Bearing



Dec. 31, 1963 E, F. BULLARD lnl, ETAL 3,115,796

BEARING Filed Jan. 2, '1962 United States Patent Oice 3,ll5,796'Patented Dec. 31, 1963 3,115,796 BEARING Edward P. Bullard lil andEdward l. Bullard IV, Fallfield, Conn., assignors to The BullardCompany, Bridgeport, Conni, a corporation of Connecticut Filed `lan. 2,1962, Ser. No. 163,6S8 4 Claims. (Cl. 77-3) The present inventionrelates to plain bearings, and particularly to a new and improvedbearing assembly l.for the spindle of a horizontal boring machine andthe hke.

lThe tool-supporting spindle of horizontal boring mills is required torotate and to move axially under varying loads at varying speeds duringworking operations with an absolute minimum of deflection and/orchatter. lhe problems encountered in the past in attempting to achievethis result have been diflicult, and their solutions have left much tobe desired.

The principal object of the present invention is to provide a bearingmounting for the spindle of a horizontal boring mill and the like inwhich a minimum of spindle deflection and/ or chatter occurs during theperformance of working operations by -the mill.

Another object of the invention is to provide such a bearing which willbe adjustable to eliminate radial clearal'lCe.

Still another object of the invention is to provide such a bearing inwhich chatter is eliminated.

Another object of the invention is to provide such a bearing in whichthe bear-ing itself prevents the transfer of heat.

Still another object of the invention is to provide such a bearing thatwill have a long life.

in one aspect of the invention, the spindle of a horizontal boring millmay be mounted in ball bearings within a non-rotatable, axially movablehousing. The housing may support pinions in mesh with a rack that is xedagainst axial movement in the frame lof the machine so that upon therotation of the pinions, axial movement of the housing, and wi-th it therotatable spindle, will be effected. The forward end of the spindle maybe spline keyed to a rotatable, axially fixed sleeve that may be rivenfrom the headstock of the mill.

ln another aspect of the invention, the forward end of the sleeve mayhave internally mounted therein a bushing having a tapered internalsurface, within which may be mounted a mating bushing having a taperedexterior surface and a cylindrical interior surface journaling therotatable spindle.

rShe bushing journaling the rotatable spindle has a continuousuninterrupted cylindrical inner surface and preferably is made from alaminated base material such as paper, woven fabric, asbtstos, glass orsynthetic fibers impregnated with a thermosetting plastic such as asynthetic varnish and bonded together under heat and pressure.

in still another aspect of the invention, a similar bushing may belocated at the rear of the rotatable sleeve. It has been found that themovement of the tapered, nonmetallic bushings at each end of the sleevetoward each other causes the elimination-of-Wear clearance between themand lthe spindle; that the spindle is prevented from chattering; thatsubstantially little heat is transferred through the non-metallicbushings; and that the bearing has a long life.

The above, other objects and novel features o-f the invention willbecome apparent from the following specification and accompanyingdrawing which i-s merely exemplary.

ln the drawing:

FIG. 1 is a sectional plan view of a spindle of a horizontal boring millto which the principles of the invention have been applied; and

FIG. 2 is a sectional view taken substantially along line 2--2 of FIG.l.

Referring to FlGS. l and 2, the principles of the invention are shown asapplied to a rotatable and axially movable spindle l@ of a machine toolsuch as a horizontal boring mill, hving one end connected to a gear andrack construction ll. A non-rotatable housing l?, supports the righthandend of the spindle lll for rotation within antifction bearings i3 andi4. A rack l5' is fixed to a housing 16 of a tool head (not shown),which latter supports the non-rotatable housing 12 for axial movementwith the spindle 1t?. The rack |15 meshes with spur gear means 17 fixed-to a shaft 18. The shaft 18 is journaled in the housing l2 with one endof said shaft fixed to a gear 19. The gear I9 meshes with a gear Ztlfixed to a shaft 21. One end of the shaft 2l is fixed to a bevel gear 22that may `be connected through proper gearing to a power source (notshown).

From the foregoing it is evident that lrota-tion of the bevel `gear 22in either direction will eect the rotation of spur gear 17. Rotation ofthe spur gear i7, which is in mesh with the rack l5, wil-l cause axialfeeding movement of the spindle lll.

The spindle lo may be mounted :for axial movement within a hollow shaft23. The hollow shaft 23 may be supported by antifriction bearings 2d and25 mounted within a housing of the tool head (not shown). rl`he hollowshaft 2,3 may be provided at each end with counterbores 25 and 27 and akey way 2S in which is fixed a key 29. The key 2Q' is adapted tocooperate with an elongated key way 3d within the spindle Elli. Gears3l, which are also fixed to `the hollow shaft 23, may be connectedthrough proper gearing to a power source (not shown).

From the foregoing it is evident that rotation of gears 3l will causethe rotation of spindle lill through key 2%.

The counterbore 26 may receive a fixed bushing 32 having a taperedinside diameter 353` that cooperates with a tapered adjustable bushing34. The bushing 34 may be provided with a flange 3S that cooperates withadjustable nuts 36 and 37. The adjustable nuts 36 and 37 are threadinglymounted in a threaded hole 3e of the hollow shaft 23. The taperedbushing 34 may be made from a. laminated base material such as paper,woven fabric, asbesto-s, glass, or syntheic fibers impregnated with athermosetting plastic such as a synthetic varnish or the like and bondedtogether under heat and pressure. One such material is known in thetrade as Spauldite manufactured -by the Spaulding Fibre Company, Inc.,of Tonawanda, New York. it has been found that when such a plastic,externally tapered bushing having a cylindrical inner surface is forcedinto a rigid, stationary, internally tapered bushing, the internal,cylindrical, inner diameter of the plastic bushing will reduce indiameter uniformly throughout its length.

From the foregoing it is evident that adjustable rotation of the nuts 36and 37 will effect Ithe axial movement of the tapered bushing 34, takingup any play between it and spindle 10' that might develop due to wear.

The counterbore 27 may be provided with a fixed bushing 39 also having atapered inside wall ttl that cooperates with a tapered adjustablebushing 4l which may be made from the same material as bushing 34. Thebushing 411 may be threaded to a flange ring 42 that cooperates with aspacing ring 43 as well as with spacing blocks 441. The blocks 44 aremounted within slots 45 in the end of shaft 23 (FIG. Z), in abuttingrelation with the end surface d6 of said slo-ts. The blocks 44 may beundercut at 46 to partially receive the flange ring The spacing ring 43is adapted to abut a surface 47 Ion a gear i8 that is fixed to thehollow shaft 23 by cap screws 49;

From the foregoing it is evident that by employing blocks 44 and rings43 of different thicknesses, laxial adjustment of the tapered bushing 4dcan be etected, thus adjusting the radial clearance between it and thespindle lll.

As previously described, the tapered bushings 3d and 4d preferably areof non-metallic material, thus preventing the transfer of heat to orfrom the spindle lll.

Although the various features of .the new `and improved adjustablespindle bushings have been shown and described in detail to tullydisclose one embodiment of the invention, it will be evident thatchanges may oe made in such details and certain features may be usedwithout others without departing from the principles of the invention,

What is claimed is:

1. ln a horizontal boring mill, a spindle; a plain bearing for saidspindle comprising a rotatable, axially lixed sleeve through which saidspindle extends; means for spline-keying said sleeve Vto said spindle sothat said spindie can be rotated as well as axially moved; anon-metallic bearing bushing having a cylindrical inner surface and atapered outer surface between said spindle and said sleeve, saidnon-metallic bushing having a continuous, noninterrupted annular crosssection throughout its entire effective length; metal mating surfacemeans between said bearing bushing and said sleeve; and means foraxially moving said bearing bushing relative to said mating surfacemeans for uniformly contracting the internal diameter of said bearingbushing to eliminate wear clearance between said non-metallic bearingbushing and spindle.

2. ln a horizontal boring mill, a spindle; a plain bearing for saidspindle comprising a rotatable, axially iixed sleeve through which saidspindle extends; means for spline-keying said sleeve to said spindle sothat said spindle can be rotated as well as axially moved; separatenon-metallic bearing bushings having cylindrical inner surfaces andtapered outer surfaces between said spindle and said sleeve and locatedat each end of said sleeve, said non-metallic bushings havingcontinuous, noninterrupted annular cross sections throughout theirentire eileetive length; metal mating sunface means between said bearingbushings and said sleeve; and means for axially moving said bearingbushings relative to said mating surface means for uniformly contractingthe internal diameter of said non-metallic bearing bushings to eliminateWear clearance between said bearing bushings and spindle.

3. In a horizontal boring mill, a spindle; a plain bearing for saidspindle comprising `a rotatable, axially fixed sleeve through which saidspindle extends; means for spline-keying said sleeve to said spindle sothat said spindle can be rotated as well as axially moved; anon-metallic bearing bushing having a cylindrical inner surface and atapered outer surface between said spindle and said sleeve, saidnon-metallic bus-hing having a continuous, noninterrupted annular crosssection throughout its entire effective length; a metallic bushinghaving a cylindrical outer surface and a tapered inner surface betweensaid bearing bushing and said sleeve; and means `for axially moving oneof said bushings relative to the other for contracting the internaldiameter of said non-metallic bearing bushing to eliminate wearclearance between said bearing bushing and spindle.

4. `In a horizontal boring mill, a spindle; a plain bearing for saidspindle comprising ya rotatable, axially hxed sleeve through which saidspindle extends; means for spline-keying said sleeve to said spindle sothat said spindie can be rotated as well as axially moved; sepmatenon-metallic bearing bushings having cylindrical inner surfaces andtapered outer surfaces between said spindle and said sleeve and locatedat each end of said sleeve, said non-metallic bushings havingcontinuous, noninterrupter annular cross sections throughout theirentire effective lengths; a metallic bushing having a cylindrical outersurface and a tapered inner surface between each bearing bushing andsaid sleeve; and means for axially moving one of said bushings at eachend of said sleeve relative to the other for uniformly contracting theinternal diameter of said non-metallic bearing bushings to eliminatewear clearance between ysaid bearing bushings and sleeve.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A HORIZONTAL BORING MILL, A SPINDLE; A PLAIN BEARING FOR SAIDSPINDLE COMPRISING A ROTATABLE, AXIALLY FIXED SLEEVE THROUGH WHICH SAIDSPINDLE EXTENDS; MEANS FOR SPLINE-KEYING SAID SLEEVE TO SAID SPINDLE SOTHAT SAID SPINDLE CAN BE ROTATED AS WELL AS AXIALLY MOVED; ANON-METALLIC BEARING BUSHING HAVING A CYLINDRICAL INNER SURFACE AND ATAPERED OUTER SURFACE BETWEEN SAID SPINDLE AND SAID SLEEVE, SAIDNON-METALLIC BUSHING HAVING A CONTINUOUS, NONINTERRUPTED ANNULAR CROSSSECTION THROUGHOUT ITS ENTIRE EFFECTIVE LENGTH; METAL MATING SURFACEMEANS BETWEEN SAID BEARING BUSHING AND SAID SLEEVE; AND MEANS FORAXIALLY MOVING SAID BEARING BUSHING RELATIVE TO SAID MATING SURFACEMEANS FOR UNIFORMLY CONTRACTING THE INTERNAL DIAMETER OF SAID BEARINGBUSHING TO ELIMINATE WEAR CLEARANCE BETWEEN SAID NON-METALLIC BEARINGBUSHING AND SPINDLE.